People keep posting this Wikipedia link as if it ended discussion on the topic. An idea is not automatically true just because it has a Wikipedia article. Even the linked article has quotes from people who disagree:
Thomas Jefferson had already addressed the notion of a tolerant society in his first inaugural speech, concerning those who might destabilise the United States and its unity, saying, "...let them stand undisturbed as monuments of the safety with which error of opinion may be tolerated where reason is left free to combat it."
Jefferson may have changed his mind had he seen the horrors that Nazi ideology led to in WW2 -- and may do so again, the way Europe (and the US) is going.
Maybe he would have, maybe he wouldn't have. We'll never know. We'll certainly never know if Jefferson would have thought the wholesale slaughter of jews to be an appropriate topic to broach when discussing the relative merits of the GPL vs MIT. Instead of resorting to temporally impossible hypotheticals, why not talk about people who actually had the sort of experiences you think are most relevant to the discussion?
Thomas Jefferson had already addressed the notion of a tolerant society in his first inaugural speech, concerning those who might destabilise the United States and its unity, saying, "...let them stand undisturbed as monuments of the safety with which error of opinion may be tolerated where reason is left free to combat it."